The present invention relates to a method of leveling strips and a leveling equipment of strips.
Required of strips for the production of parts for electrical and electronic apparatus are a high degree of flatness and a characteristic that parts cut out from the strips by etching do no warp. The present invention relates to a technique for rectifying the shapes of strips so that the rectified strips meet the two requirements.
The following prior arts for rectifying the shapes of strips are available.
(1) Method of rectifying the shapes of strips with a tension leveler PA1 (2) Method of rectifying the shapes of strips by low-temperature annealing
By using this method, the flatness of the strip can be improved below 0.5% in terms of the ratio of the height of a circular arc to the length of its chord, but the residual stress in the strip is high, causing parts cut out from the strip by etching to warp to a significant degree. PA2 By using this method, the residual stress in the strip can be reduced below 50 N/mm.sup.2 so that parts cut out from the strip develop no substantial warps, but the flatness of the strip is over 1.0% in terms of the ratio of the height of a circular arc to the length of its chord.
In accordance with the above, the object of the present invention is to provide a leveling method and a leveling technique which secure a high degree of flatness of strips and give strips a characteristic that parts cut out from them by etching do not warp.